Prevent start of print glob
Printing with PLA, but different brands (Prusament and Filamentum). Often with the Filamentum brand the filament will start flowing out of the nozzle when the nozzle reaches the print temp (215C). I clean off the nozzle immediately before printing but by the time the mesh bed leveling is done and the print starts there is a little bit of filament out of the nozzle and when the print starts there is often a little glob that gets left on the bed, sometimes on the external perimeter and other times gets dragged into the first layer of the print itself.
This does not usually happen with the Prusament filament. The filament does not start flowing when the nozzle is heated, or if it does it is very slow and not much comes out.
Is this just a matter of reducing the nozzle temp a bit for the Filamentum? If so, what temp is recommended?
RE: Prevent start of print glob
Many people alter their start g-code to do MBL at a lower temp (160). The Mini does this too now.
Then, just before starting, it heats up to final print temp, avoiding the ooze and blob.
RE: Prevent start of print glob
You can avoid this by using a 2-step filament warmup process in your startup gcode. The idea is that you only warm the filament to a "no ooze" temperature as the bed heats. You do want the filament soft so any leftover ooze won't cause problems during mesh bed leveling. I use 160C but others go higher. The important thing is that it's warm enough that most filaments will bend if a bit bumps into the bed. Then you wait for the bed to warm and mesh bed leveling to compete with the nozzle only at that no-ooze temp. Once everything is actually ready to print, you warm the nozzle up to final print temps. That temp and the amount of ooze vary by filament.
Interestingly, Prusa seems to have implemented this on the Mini. I've got a documented example here you can examine for details.
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RE: Prevent start of print glob
Thanks guys. I'll check out modifying the g-code and post any follow up questions if I have them.
RE: Prevent start of print glob
You can avoid this by using a 2-step filament warmup process in your startup gcode. The idea is that you only warm the filament to a "no ooze" temperature as the bed heats. You do want the filament soft so any leftover ooze won't cause problems during mesh bed leveling. I use 160C but others go higher. The important thing is that it's warm enough that most filaments will bend if a bit bumps into the bed. Then you wait for the bed to warm and mesh bed leveling to compete with the nozzle only at that no-ooze temp. Once everything is actually ready to print, you warm the nozzle up to final print temps. That temp and the amount of ooze vary by filament.
Interestingly, Prusa seems to have implemented this on the Mini. I've got a documented example here you can examine for details.
OK so I'm finding that linked example a bit complicated to follow (I'm totally new). Here is my current start g-code:
M862.3 P "[printer_model]" ; printer model check
M862.1 P[nozzle_diameter] ; nozzle diameter check
M115 U3.8.1 ; tell printer latest fw version
G90 ; use absolute coordinates
M83 ; extruder relative mode
M104 S[first_layer_temperature] ; set extruder temp
M140 S[first_layer_bed_temperature] ; set bed temp
M190 S[first_layer_bed_temperature] ; wait for bed temp
M109 S[first_layer_temperature] ; wait for extruder temp
G28 W ; home all without mesh bed level
G80 ; mesh bed leveling
G1 Y-3.0 F1000.0 ; go outside print area
G92 E0.0
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line
G92 E0.0
M221 S{if layer_height<0.075}100{else}95{endif}
How do I edit this to include 2 step warmup?
RE: Prevent start of print glob
Worth noting that filaments ooze more as they absorb moisture due to bubbling and steam production.
You may also want to look at drying your filament to see if it improves the situation.
RE: Prevent start of print glob
Worth noting that filaments ooze more as they absorb moisture due to bubbling and steam production.
You may also want to look at drying your filament to see if it improves the situation.
I believe the filament is dry, at least I don't hear any popping or see any steam as the filament comes out. I store the filament in plastic bags with desiccant.
RE: Prevent start of print glob
Popping or steam usually only happens when it is severely wet. Trace amounts of moisture can still cause it to swell/ooze as it heats but not exhibit other symptoms.
RE: Prevent start of print glob
Thanks guys, I got it figured out. Works a treat!